Add a runtime data dependency on icudtl.dat in the GN build.

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//third_party/icu/config.gni")
 
 # Meta target that includes both icuuc and icui18n. Most targets want both.
 # You can depend on the individually if you need to.
 group("icu") {
   deps = [
@@ skipping 499 matching lines @@
         ]
       } else {
         sources = [
           "source/data/in/icudtl.dat",
         ]
       }
 
       outputs = [
         "$root_out_dir/icudtl.dat",
       ]
+
+      data = [
+        "$root_out_dir/icudtl.dat",
+      ]
     }
   }
 } else {
   if (is_win) {
     # On Windows the target DLL is pre-built so just use a copy rule.
     copy("icudata") {
       sources = [
         "windows/icudt.dll",
       ]
       outputs = [
         "$root_out_dir/icudt.dll",
       ]
+
+      data = [
+        "$root_out_dir/icudtl.dll",
+      ]
     }
   } else {
     source_set("icudata") {
       # These are hand-generated, but will do for now.
       #
       # TODO(GYP): Gyp has considerations here for QNX and for the host toolchain
       #  that have not been ported over.
       if (is_linux) {
         sources = [
           "linux/icudtl_dat.S",
         ]
       } else if (is_mac) {
         sources = [
           "mac/icudtl_dat.S",
         ]
       } else if (is_android) {
         sources = [
           "android/icudtl_dat.S",
         ]
       } else {
         assert(false, "No icu data for this platform")
       }
       defines = [ "U_HIDE_DATA_SYMBOL" ]
     }
   }
 }